Heated Steering Wheel System Steering Wheel Does Not Heat Up When Heated Steering Wheel Switch Is Pressed

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

INSPECT STEERING WHEEL ASSEMBLY (THERMISTOR·HEATER·THERMOSTAT)

INSPECT SPIRAL WITH SENSOR CABLE SUB-ASSEMBLY

CHECK STEERING HEATER SWITCH

CHECK HARNESS AND CONNECTOR (STEERING HEATER SWITCH - SPIRAL W/ SENSOR CABLE SUB-ASSEMBLY)

CHECK HARNESS AND CONNECTOR (IG CIRCUIT)

CHECK HARNESS AND CONNECTOR (IG CIRCUIT)

CHECK HARNESS AND CONNECTOR (SPIRAL WITH SENSOR CABLE SUB-ASSEMBLY BODY GROUND)

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

HINT:

1. Inspect the fuses for circuits related to this system before performing the following inspection procedure.
   
2. The steering heater unit is built into the steering wheel assembly which cannot be disassembled. Therefore, when the steering heater unit has a malfunction, replace the steering wheel assembly.
   

1. Disconnect the B steering wheel controller connector.
   

2. Measure the resistance according to the value(s) in the table below.
   

   Standard Resistance:

   Tester Connection	Condition	Specified Condition
   B-1 (TH1) - B-2 (TH2)	10 to 30°C (50 to 86°F)	8.132 to 18.43 kΩ
   B-4 (SH1) - B-3 (SH2)	20°C (68°F)	1.89 to 2.25 Ω

   Text in Illustration

   *a	Front view of wire harness connector (to Steering Wheel Control Assembly)

1. Check the connectors and cables of the spiral with sensor cable sub-assembly.
   

   OK:

   There are no defects such as scratches, cracks, dents or damage on the connectors or cables.
   

2. Disconnect the E107 and z63 spiral with sensor cable sub-assembly connectors.
   

   
   
   
   

3. Disconnect the heated steering wheel controller connector.
   

4. Measure the resistance according to the value(s) in the table below.
   

   Standard Resistance:

   Tester Connection	Condition	Specified Condition
   z63-1 (CCU) - E107-1 (BTM)	Always	Below 1 Ω
   z63-2 (CCV) - E107-3 (ETM)	Always	Below 1 Ω
   z63-3 (CCX) - E107-2 (EHT)	Always	Below 1 Ω
   z63-4 (CCW) - E107-4 (BHT)	Always	Below 1 Ω

   
   

   Text in Illustration

   *a

   Component without harness connected (Spiral with Sensor Cable Sub-assembly)

   -

   -

1. Disconnect the G14 steering heater switch connector.
   

2. Measure the voltage according to the value(s) in the table below.
   

   HINT:

   As the circuit has a diode, perform the measurement in diode test mode, and do not mistake the polarity.

   Standard Voltage:

   Tester Connection (Positive (+) tester probe - Negative (-) tester probe)	Condition	Specified Condition
   G14-3 (IG) - G14-7 (+)	Always	Below 1.25 V
   G14-6 (IN) - G14-7 (+)	Steering heater switch is pushed	Below 1.25 V

3. Measure the resistance according to the value(s) in the table below.
   

   Standard Resistance:

   Tester Connection	Condition	Specified Condition
   G14-3 (IG) - G14-6 (IN)	Steering heater switch is pushed	Below 1 Ω
   G14-3 (IG) - G14-6 (IN)	Steering heater switch is not pushed	10 kΩ or higher

1. Disconnect the G14 steering heater switch connector.
   

2. Disconnect the E107 spiral with sensor cable sub-assembly connector.
   

3. Measure the resistance according to the value(s) in the table below.
   

   Standard Resistance:

   Tester Connection	Condition	Specified Condition
   G14-7 (+) - E107-1 (BTM)	Always	Below 1 Ω
   G14-6 (IN) - E107-3 (ETM)	Always	Below 1 Ω

1. Disconnect the G14 steering heater switch connector.
   

2. Measure the voltage according to the value(s) in the table below.
   

   Standard Voltage:

   Tester Connection	Switch Condition	Specified Condition
   G14-3 (IG) - Body ground	Ignition switch ON	11 to 14 V

1. Disconnect the E107 spiral with sensor cable subassembly connector.
   

2. Measure the voltage according to the value(s) in the table below.
   

   Standard Voltage:

   Tester Connection	Switch Condition	Specified Condition
   E107-4 (BHT) - Body ground	Ignition switch ON	11 to 14 V

1. Disconnect the E107 spiral with sensor cable sub-assembly connector.
   

2. Measure the resistance according to the value(s) in the table below.
   

   Standard Resistance:

   Tester Connection	Condition	Specified Condition
   E107-2 (EHT) - Body ground	Always	Below 1 Ω